This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-151431, filed May 23, 2000, the entire contents of which are incorporated herein by reference.
This invention relates to a monitoring system for apparatuses in an electric power installation, such as generating stations, substations, or switchyards, and a method of monitoring such apparatuses.
In a substation, there are generally provided power apparatuses. These include power switching modules for connecting/disconnecting high-voltage main circuits, such as gas insulated switchgear, transformers, and reactors. These apparatuses are required to improve reliability, reduce the frequency of maintenance, prevent a failure from occurring, and take measures at an early stage in case of a failure. To meet these requirements, monitoring systems for power apparatuses have been proposed.
FIG. 1 shows a conventional apparatus monitoring system. In the apparatus monitoring system, various physical characteristics and chemical characteristics related to apparatus condition are measured by a variety of sensors 41. The output signals from the sensors 41 are processed by a number of measuring sections 42, which convert the signals into measurement data. Thereafter, the measurement data is gathered by an acquisition unit 43 and then displayed on a data display unit 44.
The measurement data acquisition unit 43 and data display unit 44 are located in.the main building of the electric power installation. When data indicating an abnormality in an apparatus has been measured, the indication of the abnormality is displayed as data on the data display unit 44 in the main building of the electric power installation. The data on the display unit enables the user to recognize the abnormality. Furthermore, when data indicating an abnormality in an apparatus has been measured, data items concerning the abnormality are gathered together. The gathered information is transmitted in the form of summarized data about the switchgear to the monitoring unit 45. This monitoring unit 45 then reports the information to a higher-order control station in a distant place.
The data measured by the apparatus monitoring system, together with time data supplied from a local clock module in the apparatus monitoring system, is stored in the measured data acquisition unit 43.
In an apparatus monitoring system that monitors, for example, the gas-insulated switchgear in a substation, the instantaneous value measurement data items include gas pressure, partial discharge, oil pressure, and the operating time of a switch. The accumulated measurement data includes the contact wear.
A device for measuring the contact wear of a switch has been disclosed in Jpn. Pat. Appln. KOKOU Publication No. PH08-021280 which corresponds to Jpn. Pat. Appln. KOKAI Publication PH64-014832. The device is based on the fact that the wear of the contact of a circuit breaker is determined by the value of the current that is interrupted.
The conventional apparatus monitoring system of FIG. 1, however, has the following problems.
The first problem is that, although the measured data can be checked on the data display unit installed in the main building of an electric power installation, only limited information about the occurrence of the abnormality is transmitted to the central control station for controlling the operation of apparatuses.
Therefore, when an abnormality has occurred in an apparatus in an electric power installation and the abnormality has been sensed, checking detailed information about the abnormality requires maintenance personnel to go to the site and check the data displayed on the data display unit 44 in the main building. This increases the burden on the maintenance personnel, causes a delay in taking measures in case of a failure, impairs the operation of the apparatus, and degrade the efficiency of the facilities.
The second problem concerns time-tagging of data.
In the conventional apparatus monitoring system, for time-tagging of the measured data, the time of the local clock device included in the apparatus monitoring system is used. The time data from such a local clock device is inaccurate and the apparatus monitoring system is not synchronized with other systems, including protection and control systems.
Consequently, it is impossible to analyze changes in the state of the apparatus accurately with respect to time. This makes it difficult to determine accurately expected restoring time when the apparatus has malfunctioned. The data measured by the apparatus monitoring system cannot be checked time-sequentially against the data measured by another system, which makes it impossible to use the former data as analysis data when an abnormality has been sensed.
Furthermore, the conventional apparatus monitoring system is based on the state of the system and is independent of the systems, which protect and control the operation of the apparatus.
Therefore, when the data related to the service life is measured from data about the operating state quantity of the apparatus as is the case for contact wear quantity of the breaker, it is necessary to provide the apparatus monitoring system with a separate sensor for taking in data about the operating state quantity of the apparatus. This makes the system redundant and more complex and impairs the economy of the system.
A first object of the present invention is to provide a highly economical, high-performance apparatus monitoring system for equipment installed in an electric power installation. The invention improves the function of the system by making it easier to check the condition monitoring data at a remote place, thereby helping save labor, take measures more easily and quickly in case of a failure, and improve the operation of the apparatus and system and further the economy of the whole system.
Another object of the present invention is to provide a higher-performance apparatus monitoring system which improves the function of the system by making it possible to compare the condition monitoring data obtained in the system with the data measured by another system in the same time sequence. This will improve the data management, thereby helping take measures much more easily and quickly in case of a failure.
Another third object of the present invention is to provide a more economical and higher-performance apparatus monitoring system which not only simplifies the system as much as possible but also makes a sophisticated judgment on the state of the apparatus on the basis of the data from another system.
Another goal of the present invention is to provide a business model for an apparatus monitoring method capable of monitoring apparatuses installed in the user""s electric power installation, creating some useful consulting data from the monitoring data at the time of maintenance or inspection or in case of a failure, and providing the user with the consulting data.
According to the present invention, there is provided an apparatus monitoring system, which monitors an apparatus installed in an electric power installation and is connected to a communication network. This apparatus monitoring system comprises: sensors which are provided on an apparatus; a data acquisition and transmitting unit including conversion means which samples the signals from the sensors and converts the sampled signals into absolute-time-tagged digital monitoring data and transmission means for transmitting the digital monitoring data to the communication network; and a data display unit which receives the digital data from the data acquisition and transmitting unit via the communication network, converts the digital data into display data, and displays these data.
With such an apparatus monitoring system, the condition monitoring data obtained by the data acquisition and transmitting unit or the data related to the state of the monitored apparatus created on the basis of the condition monitoring data, can be checked from anywhere with the data display unit connected via the network. Therefore, maintenance personnel can check the condition monitoring data easily from a remote place, such as a control station, without going to the site, thus improving the functioning of the system. This not only helps save labor in apparatus maintenance and take action more easily and quickly in case of a failure, but also improves the operation of the apparatus and system. Furthermore, since the absolute time is tagged to the data obtained by the data acquisition and transmitting unit, an accurate analysis of changes in the apparatus state with respect to time makes it possible to display accurately the time that measures have to be taken after an abnormality has occurred in the apparatus. It is also possible to collate these time-tagged data with data measured by another system. Accordingly, the data management is improved, stepping up the function of the system, which helps take action much more easily and quickly in case of a failure.
In the apparatus monitoring system, the apparatus to be monitored is a power equipment for controlling power supply in an electric power transmission system, the apparatus monitoring system further comprises a digital protection and control unit including: means for sampling the electrical quantity data about the system controlled by the power equipment and the operating state data about the power equipment and converting the sampled data into absolute-time-tagged digital data; protection and control means for protecting and controlling the system according to the digital data; and transmission means for transmitting the digital data as electrical quantity data and operating state data to the communication network. And the data display unit receives the digital data from the data acquisition and transmitting unit and the digital data from the digital protection and control unit via the network, converts the digital data into display data related to the state of the monitored apparatus, and displays these data.
With this apparatus monitoring system, not only the data obtained by the data acquisition and transmitting unit but also the data obtained by the digital protection and control unit can be taken in via the network. In this way, the data from two systems can be combined, allowing a more sophisticated judgment to be made on the state of the apparatus. Use of the data from both systems simplifies the system as much as possible, thus improving cost effectiveness.
In the apparatus monitoring system, the apparatus to be monitored is provided in each electric power installation where electric cables are laid, and the communication network is composed of a first communication network for a local area constructed in each electric power installation and a second communication network for connecting a number of electric power installations in a wide area.
This apparatus monitoring system can be introduced easily, making use of the existing wires, without requiring new wiring work. This improves the application of the system and provides a low-cost system, taking into account the cost for system installation.
In the apparatus monitoring system, one of the data acquisition and transmitting unit, the digital protection and control unit, and the data display unit includes means for calculating an estimated value for a variable related to the deterioration of the function of each part of the apparatus. This calculation is carried out on the basis of one of or both of the condition monitoring data from the data acquisition and transmitting unit, the operating state data from the digital protection and control unit, and the electrical quantity data from the digital protection and control unit.
The one part of the apparatus corresponds to one of a switch contact and a contact of on-load tap changer (hereinafter, referred to as OLTC), and one variable related to the deterioration of the function corresponds to one of the wear condition of a switch contact and the wear condition of a OLTC.
In the above apparatus monitoring system, the expected inspection timing according to the estimated value for the variable related to the deterioration of the function of the apparatus can be displayed on the data display unit. For instance, when the estimated values for the wear condition of the switch contact, and the wear condition of the OLTC contact have been calculated, it is possible to estimate the inspection timing for the switch or the OLTC, on the basis of the obtained estimated value. In this case, maintenance and inspection work can be optimized, which improves the economy of the whole system including the monitored apparatus.
Furthermore, according to the present invention, there is provided a method of monitoring the state of an apparatus installed in a user""s electric power installation and creating necessary data. This method comprises: the step of prompting the user to enter information for identifying the performance including the ratings of the apparatus and receiving identification information; the step of receiving the monitoring data about the apparatus; the step of receiving the electrical quantity data about the system controlled by the apparatus; and the step of obtaining the basic performance data about the monitored apparatus by reference to an apparatus database on the basis of the performance identification information, calculating an estimated value for a variable related to the deterioration of the function of the monitored apparatus on the basis of the basic performance data, the received condition monitoring data, and electrical quantity data, and calculating expected inspection timing data according to the obtained estimated value.
In the method, the step of creating the estimated data includes the step of, on the basis of the obtained basic performance data for the apparatus and the received electrical quantity data, calculating, as the estimated value, the accumulated value for the one of the wear condition of a switch, the ware condition of a OLTC contact, and the elapsed service life of a transformer, and the step of calculating expected inspection timing data about the monitored apparatus on the basis of the calculated accumulated value and the obtained basic performance data.
With this method, it is possible to provide the user with the expected inspection timing data according to the estimated value for the variable related to the deterioration of the function of the user""s monitored apparatus. The expected inspection timing data is provided for the user, thereby optimizing the user""s maintenance and inspection work. Estimated data about an allowable load that does not degrade the service life of the transformer or an allowable over-load time that does not degrade the service life of the transformer under a desired load quantity is also calculated. The calculated estimated data is provided for the user, which enables the user to operate the transformer efficiently using the estimated data. Since the user need not analyze various types of data about the deterioration of the function of the apparatus and the operating efficiency or manage the apparatus database necessary for such data analysis, the burden of maintenance and inspection and of controlling the operating efficiency on the user is decreased.
Furthermore, according to the present invention, there is provided a program for executing a method of monitoring the state of an apparatus installed in a user""s electric power installation and calculating necessary data. This program comprises: receiving information for identifying the performance including the ratings of the apparatus; receiving monitoring data about the apparatus; receiving electrical quantity data about the system controlled by the apparatus; and obtaining the basic performance data about the monitored apparatus by reference to an apparatus database on the basis of the performance identification information, calculating an estimated value for a variable related to the deterioration of the function of the monitored apparatus on the basis of the basic performance data, the received condition monitoring data, and electrical quantity data, and calculating expected inspection timing data according to the obtained estimated value.
In addition, according to the present invention, there is provided a program for executing a method of monitoring the state of an apparatus installed in a user""s electric power installation and creating necessary data. This program comprises: receiving information for identifying the performance including the ratings of the apparatus; receiving electrical quantity data and operating state data about the apparatus; and obtaining the basic performance data about the apparatus by reference to an apparatus database on the basis of the performance identification information, determining an abnormality occurring in part of the monitored apparatus on the basis of the basic performance data and the received operating state data, and calculating support data according to the determined abnormality.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.